#!/bin/bash# t-out.sh# Inspired by a suggestion from "syngin seven" (thanks).TIMELIMIT=4         # 4 secondsread -t $TIMELIMIT variable <&1#                           ^^^#  In this instance, "<&1" is needed for Bash 1.x and 2.x,#  but unnecessary for Bash 3.x.echoif [ -z "$variable" ]  # Is null?then  echo "Timed out, variable still unset."else    echo "variable = $variable"fi  exit 0